A ban on sugary cereals and high fat foods aimed at children should be considered to help curb obesity, Labour has urged.
Shadow health secretary Andy Burnham said voluntary agreements with the food industry were not working and action must be taken to stop Britain storing up "huge problems" for the future.
Labour is launching a consultation into a new cap on the maximum permitted levels of fat, sugar and salt in food targeted at youngsters, which could include a 30% cap on sugar in cereals.
Mr Burnham said: "It is clear that the current voluntary approach is not working. We need to open our minds to new approaches in tackling child obesity.
"Labour wants to lead this debate. That is why we are asking the public and experts if new limits for sugar, fats and salts would be the right approach.
"Like all parents, I have bought products like cereals and fruit drinks, marketed as more healthy, that contained higher sugar levels than expected. I don't think that any parent would be comfortable with their child eating something that is 40% sugar.
"The Government has failed to come up with a convincing plan to tackle this challenge."
Labour cited a report by consumer group Which? last year that found high sugar levels in 32 out of the 50 breakfast cereals it examined, with Kellogg's Frosties the highest on 37g per 100g.
Gabriel Scally, former regional director of public health for the south west at the Department of Health, said: "The continued rise in childhood obesity is an urgent call to action and must not be ignored.
"I applaud the Labour Party for tackling the issue of the foodstuffs filling our children with the empty calories that fuel obesity. Helping parents protect and promote the future health of our children is exactly what we need to be doing."
A Department of Health spokesman said: "By working with industry through the Responsibility Deal we have helped to reduce fat, sugar and salt in foods.
"There is now less salt in the food we buy, companies are cutting and capping calories and artificial trans fats are being widely taken out of food."
The spokesman added: "We are working to reduce the amount of salt in food further, cut saturated fat consumption and we are exploring how to promote healthier food choices more widely. We also want more businesses making pledges so we get bigger results."